An embodiment relates generally to detection of water and water film thickness on a path of travel.
Precipitation on a driving surface causes several different issues for a vehicle. For example, water on a road reduces the coefficient of friction between the tires of the vehicle and the surface of the road resulting in vehicle stability issues. Detection of precipitation on a road of travel is typically determined by a host vehicle sensing for precipitation on the road utilizing some sensing operation which occurs when the precipitation is already impacting the vehicle operation such as detecting wheel slip. As a result, the vehicle must monitor its own operating conditions (e.g., wheel slip) against dry pavement operating conditions for determining whether precipitation is present. As a result, such systems may wait for such a condition to occur or may introduce excitations to the vehicle for determining whether the condition is present (e.g., generating sudden acceleration to the driven wheels for invoking wheel slip if the precipitation is present).
Moreover, individual sensing techniques typically focus on a single concept for detecting wetness of a road where each respective technique works well under certain environmental conditions (e.g., a certain level of water), but may be deficient outside of those specific environmental conditions. Therefore, it would be beneficial to have a technique that can adapt to different environmental conditions and provide reliable results.